Synthetic oxygen carriers (SOCs)

An emerging new form of blood doping is the use of Synthetic Oxygen Carriers (SOCs)—purified proteins or chemicals that have that ability to carry oxygen. They are still under development and have not been approved for human use outside of South Africa and Russia. SOCs were developed for use in crisis situations where blood transfusions are not possible or blood products are not available.  

There are several different types of SOCs available. Two of the most common types include haemoglobin based oxygen carriers (HBOCs) and perfluorocarbons (PFCs). Like red blood cells, they work to deliver this oxygen to the muscles, increasing aerobic capacity and endurance. However, they also have some additional benefits. HBOCs are not only great at tissue oxygenation, they can deliver increases in blood serum iron, ferritin and naturally occurring Erythropoietin (EPO). They can also increase CO₂ production and curb lactic acid production.

PFCs, due to their size, are able to enter the body’s tiny capillaries, providing very efficient local oxygen delivery to greater areas of the body, while the makeup of the drug also allows it to deliver oxygen to peripheral tissues.  

SOCs are still under development and being tested, and have not yet been proven safe for human use. The health risks associated with using SOCs are similar to those of EPO—increased risk of heart attack, stroke and pulmonary embolism. HBOC’s have not been found safe for human use.

A complex four-step test was made available for SOCs in 2004. Whether it will be put into use by anti-doping authorities still remains to be seen.